Bicycle-frame.



Nd. 656,735. Patentd A 28, I900. F. A. WILMUT.

BICYCLE-FRAME.

(Application filed June 11, 1900.)

(No lolodal.)

WITNESSES INVENTOR STATES v PATENT OFFICE.

FRANK A. WILMOT, OF BRIDGEPORT, CONNECTICUT, ASSIGNORTO THE WILMOT &nouns MANUFACTURING COMPANY, or SAME PLACE.

BICYCLE-FRAME.

SPECIFICATION forming part of Letters Iatent No. 656,735, dated August28, 1900.

Application filed June 11, 1900. Serial No. 19,818. 0 model-3 To allwhom it may concern:

Be it known that I, FRANK A.WILMO'I,a oiti zen of the United States,residing'at Bridgeport, county of Fairfield, State of Connecticut, haveinvented a new and useful Bicycle- Frame, of which the following is aspecification.

My invention relates to the manufacture of bicycle-frames, and has forits object to provide a bicycle-frame having ample strength to meet allof the ordinary requirements and most of the extraordinary requirementsof use and which shall be perceptibly lighter than any frame now in usewhich approximates a safe degree of strength. In other words, myinvention embodies a safe and practical maximum of strength and minimumof weight.

It is of course well understood that the two weakest points in theconstruction of both diamond frames and drop frames are the seat-posttube at or near the crank-hanger and the lower tube at or near the head,for the reason that the throw of the cranks tends to strain theseat-post tube at the crankhanger and the movements of the front wheelin use tend to strain the lower tube at the head, strains at both pointsfrequently re sulting in breakdowns and serious accidents. I havediscovered as a result of careful and extended experiments that byincreasing the diameter of the lower end of the seat-post tuberelatively to the upper end thereof and of the upper end of the lowertube relatively to the lower endthereof without appreciable variation inthe thickness of the metal at any portion of the tubes I am enabled toproduce a very much stronger frame with a given weight of metal or aframe having a required degree of strength that shall be very muchlighter than any bicycle-frame now known to the trade.

My invention is applicable to all classes of seamless and sheet-metaltubing-as, for example, the well-known clincher tubing, covered bypatents granted to me March 16, 1897, Nos. 578,799, 578,800, and578,801.

In the accompanying drawings,forn1in gpart of this specification, Figure1 is an elevation of a diamond bicycle-frame, so called, showing theapplication thereto of my novel invention; Fig. 2, an elevation of adrop bicy ole-frame, so called, illustrating the application thereto ofmy novel invention; Fig. 3, a section on the line 3 3 in Figs. 1 and 2and Fig. 4. is a section on the line at lin Figs. 1 and 2.

l0 denotes the upper tube of either a diamond or drop frame; 11, theupper rear fork; 12, the lower rear fork; 13, the head; 14, the frontfork; 15, the lower tube, and 16 the seat= post tube.

The gist of my invention lies in making the seat-post tube smallest atits upper end and largest at its lower end, with an intermediate taperand of practicallyuniform thickness throughout, and in making the lowertube smallest at its lower end and largest at its upper end, with anintermediate taper and of practically-uniform thickness throughout. Inpractice these tubes may be made straight at the ends to receive theusual attaching-lugs, (not shown in the drawings,) which project fromthe parts to which the tubes are attached, and so much of the upper endof the seat-post tube as receives the seat-post may be made of uniforminternal diameter, so as to provide for the use of an internal expanderas a means of looking a seat-post. The size of the upper and lower rearforks and the upper tube and the matter of whether said parts are of uniform diameter or tapered is not of the essence of my invention.

In Fig. l I have illustrated a diamond frame having an upper tube ofuniform diameter and in Fig. 2 I have illustrated a drop frame having anupper tube made smallest at its lower end and largest at its upper endand tapering uniformly from one end to the other in order to harmonizewith the lower tube.

Having thus described my invention, I claim- 1. A bicycle-frameincluding a seat-post tube as a member thereof, said tube being formedwith its smallest diameter at the upper end and the greatest diameter atthe lower end and an intermediate taper, the metal thereof being ofpractically-uniform thickness throughout, substantially as described. 1

2. A bicycle-frame including a lower tube as a member thereof, said tubebeing formed with its smallest diameter at the lower end and greatestdiameter at the upper end and an intermediate taper, the metal thereofbeing of practically-uniform thickness throughout, substantially asdescribed.

3. A bicycle-frame having a lower tube with its smallest diameter at thelower end and greatest diameter at the upper end and a taper betweensaid points and a seat-post tube with its smallest diameter at the upperend and its greatest diameter at the lower I in presence of twowitnesses.

FRANK A. WILMOT.

Witnesses:

A. M. WOOSTER, S. W. ATHERTON.

